Recent industry interest in standardizing the test architecture and protocol for all IC chips has resulted in the adoption (Feb. 15, 1990) by the Institute of Electrical and Electronics Engineers (IEEE) of Standard 1149.1-1990, entitled "IEEE Standard Test Access Port and Boundary Scan Architecture", which document is hereby expressly incorporated by reference. Each IC chip complying with this standard has a Test Access Port (TAP) and a Test Access Port Controller (TAPC). The standard precisely defines the manner in which communication between the IC chip via the TAP and a test driver takes place. Industry-wide adherence to the standard will allow for interchangeability of IC chips by different manufacturers, insofar as testing is concerned.